Step feeders are often used to transfer lumber from a receiving location to a delivery location, and in the process to singulate (i.e., separate) the boards and properly align the boards for further processing. Many step feeders consist of a set of moving stairs and a set of fixed stairs, both slanted at an upward angle. The set of moving stairs and the set of fixed stairs often consist of multiple levels of stairs, each level including segments along the length of the stair so that the two sets of stairs interlock with each other. The moving stairs are driven up and down along the angle of the stairs by a motor and crank shaft or other arrangement. As the moving set of stairs is driven upward, it pushes a board up, and the board catches the fixed stair at the next level as the moving stair moves back downward. The board is pushed upward by the moving stair at the next level in the same manner, and eventually reaches the delivery location.
Other step feeders have one or two sets of moving stairs, but include two moving sets of stairs interposed with each other, one set moving up while the other set moves down. However, the steps within each set of stairs move together, e.g., the step at one level moves in phase with the step at another level. This causes uneven distribution of horsepower across the cycle of the stairs. Furthermore, this arrangement may not effectively singulate the boards as they travel up the step feeder.